German Patent Application No. 197 26 120 describes a device where the central station assumes the coordinating function for media access via a protocol-oriented transmission frame referred to there as signaling periods. This transmission frame contains, in addition to the useful signal data phases, signaling data phases for the uplink and the downlink.
The method described in German Patent Application No. 197 26 120 includes the step that the position of the downlink signaling is announced in the previous downlink signaling. This method presents the problem that a subscriber (terminal) that wishes to log into the communication process has no previous information regarding the position of the downlink signaling (Broadcast Channel, BCH). Therefore, this terminal must demodulate the transmission channel until it has found a BCH and has demodulated the information about the position of the next BCH. Access to the transmission channel can therefore only take place in the following transmission frame.